1. Field of the Invention
The subject invention is directed to spinal implants, and more particularly, to a percutaneously or posteriorly introduced spinous process implant and fusion device that has a body with a detachable proximal end portion that can be readily removed to reduce the overall length and size of the implant after it has been implanted in the patient's body.
2. Description of Related Art
The spine consists of a column of twenty-four vertebrae that extend from the skull to the hips. Discs of soft tissue are disposed between adjacent vertebrae. In addition, the spine encloses and protects the spinal cord, defining a bony channel around the spinal cord, called the spinal canal. There is normally a space between the spinal cord and the borders of the spinal canal so that the spinal cord and the nerves associated therewith are not pinched.
Over time, the ligaments and bone that surround the spinal canal can thicken and harden, resulting in a narrowing of the spinal canal and compression of the spinal cord or nerve roots. This condition is called spinal stenosis, which results in pain and numbness in the back and legs, weakness and/or a loss of balance. These symptoms often increase after walking or standing for a period of time.
There are number of non-surgical treatments for spinal stenosis. These include non-steroidal anti-inflammatory drugs to reduce the swelling and pain, and corticosteroid injections to reduce swelling and treat acute pain. While some patients may experience relief from symptoms of spinal stenosis with such treatments, many do not, and thus turn to surgical treatment. The most common surgical procedure for treating spinal stenosis is decompressive laminectomy, which involves removal of parts of the vertebrae. The goal of the procedure is to relieve pressure on the spinal cord and nerves by increasing the area of the spinal canal.
Interspinous process decompression (IPD) is a less invasive surgical procedure for treating spinal stenosis. With IPD surgery, there is no removal of bone or soft tissue. Instead, an implant or spacer device is positioned behind the spinal cord or nerves between the interspinous processes that protrude from the vertebrae in the lower back. An example of a particularly useful interspinous process implant and fusion device for treating spinal stenosis is disclosed in commonly assigned U.S. Pat. No. 9,314,276 to Hess et al., the disclosure of which is incorporated herein by reference in its entirety.
The subject invention provides an improvement over this prior art interspinous implant device, by constructing the implant body with a detachable proximal end portion that can be readily removed from the remainder of the implant body after it has been percutaneously installed and positioned by a surgeon, using a specialized tool or other device. This will advantageously reduce the overall size and profile of the device.